Our crows are free-flying and kept in pairs. Originally, we housed them in two large social groups, but when the breeding season commenced (see Breeding) some birds developed territorial behaviour, and we separated them to form pairs. All groups have covered outdoor aviaries of at least 9m2 and most groups also have access to large indoor rooms (4m x 2.5m x 2.5m high). All indoor rooms are connected by a hatchway to smaller testing rooms, in which we conduct the majority of our experiments.
The crows have access to water and food at all times, except during experimental trials, but they are never food deprived. To ensure that they are motivated to participate in our experiments, we reserve their preferred food (small pieces of pig heart) as a reward which can only be obtained during trials. Daily food consists of a standard bird feed (Orlux® Universal), soaked cat biscuits, mealworms, and fresh fruit.
In their home aviaries, our crows have unlimited access to branches, sticks and children’s toys of assorted sizes and shapes. As part of the standard feeding protocol, mealworms are hidden in toys and in holes in wooden logs to facilitate ‘natural’ tool use outside experimental contexts.